What is the use of IOR (Index of Refraction).

Question: What is the use of IOR (Index of Refraction).

Answer: The index of refraction of a fiber is used in the calculation of the speed of light in the fiber, as well as many other fiber specifications. The difference between the index of refraction of the core and the cladding of a fiber also are responsible for "Total Internal Reflection" which is the basic principle behind optical fiber transmission. Differences between the IOR of the fiber and the IOR of air can create back reflections at interconnection point as well. The IOR also plays a major role in lightwave acceptance/rejection into a fiber and the acceptance angles there in, due to the differences in the air/fiber interface. Changes in the IOR within the fiber affect how the light travels through the fiber, such as step index vs. graded index.